The Devs said they want guilds to end up being a web of trade houses, so this might be one way to do that. I think if they have some kind of linking system between allied guilds, so they join AHs this system would work well.
Example, if guild A were allied with guilds B, C, D and E, their AH's would look like one AH to any of those guild members in guild A.
At the same time, Guild B might also have allied guilds with F, G, H, I and J so anyone from guild B would have a combo AH of A plus F, G, H, I and J.
The more allies, the bigger the web of guild trade houses.
What do you guys think?